Smartphone-based optical transduction for the rapid microscale assessment of iodate in table salt

Henley F Galiga; Fortunato B Sevilla

doi:10.1016/j.talanta.2021.122450

Smartphone-based optical transduction for the rapid microscale assessment of iodate in table salt

Talanta. 2021 Sep 1:232:122450. doi: 10.1016/j.talanta.2021.122450. Epub 2021 Apr 24.

Authors

Henley F Galiga¹, Fortunato B Sevilla²

Affiliations

¹ The Graduate School, University of Santo Tomas, Manila, 1015, Philippines. Electronic address: henley.galiga.gs@ust.edu.ph.
² The Graduate School, University of Santo Tomas, Manila, 1015, Philippines; Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, 1015, Philippines. Electronic address: fbsevilla@ust.edu.ph.

PMID: 34074434
DOI: 10.1016/j.talanta.2021.122450

Abstract

The measurement of iodine in table salt is vital for the successful implementation of the universal salt iodization (USI) program to fight iodine deficiency disorders (IDDs). This paper presents a smartphone-based optical transduction system for iodine measurement in table salt. The method was based on the response in the blue color space generated by the complex formed between the starch/iodide reagent and iodate in the salt sample. The parameters for the color reaction and for the image capture affected the response and were optimized. A matrix effect caused by NaCl was observed and was eliminated through matrix matching by incorporating NaCl in the standard solutions. The optimized method yielded a highly linear response to iodate concentrations ranging from 10 to 160 mg kg^-1 (r = 0.9993) with a limit of detection of 2.8 mg kg^-1. The method exhibited good accuracy and precision, based on AOAC standards. It produced results that were in agreement with those obtained using the reference method at the 95% confidence level. The smartphone performs optical transduction, as well as signal processing, to yield a display of the iodate concentration in the salt sample. The use of smartphones presents a simple, inexpensive, portable, and widely available device for on-site analysis of iodate in table salt.

Keywords: Iodate measurement; Optical transduction; Smartphone-based measurement; Table salt iodization.